Manually resettable pressure actuated switch



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April 30, 195'7 G. H. HANSEN 2,790,869

MANUALLY RESETTABLE PRESSURE ACTUATED SWITCH Filed Aug. 17, 1955 Figa- INVENTOR. MMM BY /I 7- To /PA/Eys.

United States Patent MANUALLY RESETTABLE PRESSURE ACTUATED SWITCH Gilbert H. Hansen, Batavia, Ill., assignor to Furnas Electric Company, Batavia, Ill., a corporation of Illinois Application August-17, 1953, Serial No. 374,659l

2 Claims. (Cl. 200-83) The present invention relates .in general to improvements in electric switches, and relates more specicallvto improvements in they constructionand operation of manually. resettable fluid pressure actuated electric switches.

The primary object of my present invention is to provide an-ifnproved toggle switchadapted to be opened and .closed with a. snap action, and wherein the contacts are relatively automatically movable in one directionyand relatively manually movablev in .the opposite direction.

Some of the more important specific objects of the invention are as follows:

To provide an improved electric switch unit which is adapted to be opened automatically by lluid pressure and to be thereafter reset or closed at the will of an operator..

To provide an improved toggle switch assemblage wherein the contacts are positively .opened and closed with a decided snap action.

To provide a simple but durablef electric switch comprising few sturdy parts which may be readilyconstructed and assembled.

To provide a compact toggle actuated electricswitch of the fluid pressure and manually operable type, which may be produced in various sizes and for diverse uses at moderate cost.

To provide an improved electric switch actuating toggle assembly which-may be conveniently adjusted to vary the toggle action.

To provide an improved electric switch unit which is especially adapted to control-the operationV of d heating systems wherein it is desirable to have the electric ,control circuit interrupted by .excessive pressure in the `system and to be able to restore normal operation of the system at will.

To provide various improvements in the construction and operation of automatic and manually operable electric switches f the toggle type, wherebythe safety and dependability of such devices are enchanced tof a ,maximum.

rthese and other more general objects and. advantages of this invention will be apparent fromv the following description, from which it is to be noted that ther gist of my invention is the provision of an `electric switch embodying a toggle composed of a rigid plate having a swinging end coacting with the swinging end of a. curved leaf spring and in which the toggle is adapted to be flexed in opposite directions with a pronounced snap action to efiect rapid alternate opening and closing of an electric circuit when lluid and manual pressures are alternately applied to opposite sides of the toggle plate.

A clear conception of the features constitutingthe present improvement, and of the construction and operation of a typical commercial switch embodying the invention, may be had by referring to the drawing accompanying and forming a part of this specification in which like reference characters designate the same or similar parts in the various views.

Fig. 1 is a verticalsection.through oneofthe improved toggle operated electric switches, showing the contacts 2 iny open position, the. section havingbeenl taken alongthe irregular line 1--1 .of Fig..3;

Fig. 2 vis asimilar vertical section lthrough the same electric switch assemblage, but showing the contacts in closed position, the lower lluidipressure supply member having been omitted;

Fig. 3 is a side elevation of the same electric switch unit, looking toward the .toggle plate fulcrum adjusting mechanism;

Fig. 4 is atop view of the same toggle switch; and

Fig. 5 is a bottom View of the electric switch assembly with the lower uid pressure supply member-and `a portion of the Huid .pressure actuated diaphragm omitted.

While the invention .has been shown anddescribed herein as being advantageously applicable to toggle switchesadapted to break ani electric circuit when the actuating uid pressure becomes excessive, and to completethe circuit by manual actuation, it isv not myv desire or intention to unnecessarilyr limit the use of the improvements to such a unit; and it is also contemplatedlt-hat specific descriptiveterms employed herein be given the broadest possible interpretation consistent with the disclosure.

Referring to the= drawing, the improved manually resettable fluid pressure actuated switch shown therein by way of illustration, comprises in general a main composite frame consisting of l a cup-shaped base 7 having spaced fulcrums 8; 9 associated therewith, and a contact housing 10 secured to the base 7 g a flat and rigid toggle plate 11 having one end pivotally cooperable with the fulcrum 8', an .v8-shaped toggle leaf spring 12 having one. end pivotally cooperable-with the other fulcrum 9 while its opposite swinging end 13 coacts withk the opposite swinging end of the plate 11 to form a toggle; a pair of laterally spaced fixed contacts 14 confined within the housing 1l); a movable contact element 15 cooperable with the iixed contacts 14 within they housing 10; a'iluid pressure actuated plunger 16 eooperable with one face of the toggle plate 11am cause-the toggle spring-12 to displace the toggle and the -movable Contact element 1S in one direction with a snap action; a manually displaceable slide 17 supporting the contact. element 15 and having an end engageable with` the opposite face of the toggle plate/11 to cause the toggle spring 12 to displace the toggley in the reverse direction with asimilar snap action; and a helical compressionispring 13 interposed between the housing 10 and the movable lcontact element 15 for promptly completing or closing. the electric circuit when the toggle is reversely displaced.

The cup-shapedbase 7 of the main frame maybe formed of durable :sheet metal, and has a pair of oppositely disposed integral extensions or fingers 20 adaptedto be projected through opposite side openings in the housing 10 andbent over at their outer ends 21 as shown in Figs. l tof4 inclusive, so as to lirmly clamp the frame sections together. The togglefulcrum 9for the leaf spring 12 may be formed directly -in one side wall of the base 7, but the toggle fulcrum 8 of the Hat plate 11 is preferably formed in the medial portion of an L-shaped sheet metal bracket 22 Aone end of which ispivoted within and projects through an opening 23 'in the opposite side wall of the base 7 while its opposite tree-end portion is engaged by anadjusting screw 24 threaded inthe adjacent base wall. By manipulating .this screw 24,.tl1e free end of the bracket 22 may beswung about yits pivoted end at the opening 23 to yvary the position of the toggle fulcrum 8 and to therebyaccelerate or diminish the snap action of the toggle.

The flat. toggle. plate 11 is preferably formed of relatively rigid sheet metalA suiciently thin to provide pivot edges Vatits opposite ends onel of which pvotally engages the adjustable fulcrum 8, while the other edge likewise engages the V-shaped swinging end 13 of the toggle spring 12. The niedially curved toggle leaf spring is preferably formed of highly resilient sheet material and of S-shape, although not necessarily so, since any other curved shape which will insure the desired snap action of the toggle may be utilized. The pivoted end of the toggle leaf spring 12 and which coacts with the fixed fulcrum 9, is also of pivotal formation, but the swinging end of this spring 12 1s bent into V-shape so as to provide an effective pivot seat for `the thin edge at the swinging end of the toggle plate 11. The interior of the cup-shaped frame base 7 and within which the toggle is confined, should be of suflicient depth to permit free flexing of the toggle elements and to provide stops for limiting the movement of the toggle elements in opposite directions.

The switch contact housing 10 is formed of electrical insulating material and is provided at its outer portion between the openings through which the clamping fingers extend, with an integral dome 26 within which the slide 17 is longitudinally movable and in which the compression spring 18 is confined. The portion of the housing 10 remote from the dome 26 is provided with a rectangular recess 27 within which a pair of superimposed plates 28, 29 formed of electrical insulation are firmly held by the clamping lingers 20, and of which the plate 28 pro vides a direct support for the terminal bars 30 to which the fixed contacts 14 are secured, while the other plate 29 snugly engages the brim of the cup-shaped base 7. The terminal bars 30 project diagonally from within the housing 10 through sloping slots formed in this housing adjacent to the recess 27, to the housing exterior, and are provided at their outer ends with terminal screws 31, as illustrated in Figs. 3 and 4.

The fixed contacts 14 may be circular as shown or of any other desired shape, and the movable contact element 1.5 which is adapted to bridge and interconnect the fixed contacts 14, is formed of good electric current conducting metal and provides spaced but united movable contacts cooperable with the adjacent fixed contacts. The movable contact element 15 is of substantially elliptical shape as shown in Fig. 4, and is penetrated centrally by the manually operable slide 17 which has medial shoulders 33 toward which the movable contact element 15 is constantly pressed by the compression spring 18, and the slide 17 is preferably formed of electrical insulation and is guided near its opposite ends by the housing dome 26 and by the plate 29.

While the slide 17 is manually movable into engagement with one face of the toggle plate 11 to trip the toggle in one direction, the plunger 16 is automatically movable into engagement with the opposite face of the toggle plate 11 to throw the toggle across dead center in the opposite direction. As depicted, the plunger 16 is guided for longitudinal movement or reciprocation through alined openings in the bottom of the cup-shaped base 7 and in an inverted cup-shaped disk 35 rigidly secured to the base 7. The outer end of the plunger has a bearing plate 36 secured thereto and which coacts with a flexible diaphragm 37 formed of iubber or the like, and which is clamped to the disk by a fluid supply casing 38 and bolts 39. The casing 38 is secured to a supporting nut 40 and forms an enclosed chamber 41 to which fluid under pressure may be admitted through the nut 40 and through a small central opening in plate 42 secured to the casing 38, and the nut 40 may be utilized to support the entire switch unit while the actuating fluid may be derived from any suitable source.

When the improved toggle switch has been properly constructed, assembled and installed as above described, its normal operation is substantially as follows. With the various parts of the assemblage in the position shown in Fig. l, the movable contacts are in open position and the Contact element 15 is being held in such position against the action of the compression spring 18 by the slide 17 while the toggle spring 12 and plate 11 which have caused the toggle to be thrown across dead center away from the fluid pressure actuated plunger 16 are stopped against the plate 29. The switch will then be retained in open position until the fluid pressure within the chamber 41 drops sufficiently to permit the plunger 16 to be retracted or moved away from the toggle. Manual pressure may then be applied to the outer end of the slide 17 whereupon the inner end of this slide will throw the toggle across dead center in the opposite direction with a pronounced snap action, thereby releasing the movable contacts and permitting the compressed spring 18 to quickly snap the contact element 15 into closed position in engagement with the fixed contacts 14, as illustrated in Fig. 2.

The various movable parts of the assemblage will then be retained in closed position until the fluid pressure in the chamber 41 again increases sufficiently to cause the plunger 16 to throw the toggle across dead center away from the fluid pressure source, whereupon the slide 17 and the movable contact element 15 will be quickly displaced to open position with respect to thc fixed contacts 14, with a similar snap action while the helical spring 18 will again be compressed, as in Fig. 1. When the toggle is thrown in either direction across dead center, the toggle leaf spring 12 is placed under considerable tension and acts to effect opening and closing of the switch with a decided snap action, and -this action may be readily aug mented or diminished by merely manipulating the adjusting screw 24 with an ordinary screw driver or other similar implement. When the switch is being opened, the lateral projections 33 on the medial portion of the slide 17 move the contact element 15 away from the fixed contacts 14 and cause the element 15 to compress thc spring 18; and when the switch is closing, the compressed spring 18 quickly brings the contact element 15 into engagement with the fixed contacts 14 while the slide 1.7 and its projections 33 are being moved toward the toggle.

From the foregoing detailed description it will be apparent that the present invention provides a simple, compact and durable toggle switch unit in which the contacts are adapted to be opened and closed with great rapidity and are positively held in both open and closed position until either of these positions is altered as when the fluid pressure in the chamber 41 reaches a predetermined value, or manual pressure is applied to the slide 17. The switch contacts are well insulated and protected by the housing 10 and the insulation plates 28, 29, and thc toggle is likewise protected by the cup-shaped base 7. The formation of the base 7 with the clamping fingers 20 provides simple but effective means for 'assembling the switch unit, and the only adjustment required after the parts have been assembled is manipulation of the screw 24 which may be easily accomplished from the exterior of the enclosure. The nut 40 also provides simple means for mounting the switch assemblage at a readily accessible locality, and the improved switch has proven highly satisfactory in actual use especially as a safety control for fluid pressure heating systems. The unit is also composed of few simple parts which may be readily manufactured `and assembled at moderate cost, and may be built in various sizes for diverse uses.

It should be understood that it is not desired to limit this invention to the exact details of construction and operation of the manually reset pressure actuated electric switch, herein specifically shown and described, for various modifications within the scope of the appended claims may occur to persons skilled in the art.

I claim:

l. In an electric switch, a rigid frame comprising a cup-shaped base provided with opposite side walls having thereon spaced fulcrums and a contact housing secured to the brim of the base, a rigid toggle plate having one end pivotally seated within one of said fulcruins, an S-shaped flexible toggle spring having one end pivotally seated within the other of said fulcrums while its opposite swinging end pivotally coacts with the opposite swinging end of said rigid plate to for-m a toggle, a fixed contact mounted in said housing, a movable contact con fined within said housing and being cooperable with said fixed contact, a movable contact carrier cooperable directly with one face of said rigid plate to cause said exible spring to displace said toggle and said movable contact in one direction with a snap action, and liuid pressure actuated means cooperable directly with the opposite face of said rigid plate to cause said flexible spring to displace said toggle and said movable Contact in the opposite direction with a snap action, said spring being alternately directly engageable with said base and with said housing to positively limit the displacement of said toggle in opposite directions.

2. In an electric switch, a rigid frame comprising a cup-shaped base provided with opposite side walls having thereon spaced Xed and relatively movable fulcrums and a contact housing secured to the brim of the base, a rigid toggle plate having one end pivotally seated within said movable fulcrum, an S-shaped flexible toggle spring hav ing one end pivotally seated within said xed fulcrum while its opposite swinging end pivotally coacts with the opposite swinging end of said rigid plate to form a toggle, a xed contact mounted in said housing, a movable contact cooperable with said fixed contact, a movable contact carrier resiliently urged toward contact closing position and being cooperable directly with one face of said rigid plate to cause said flexible spring to displace said toggle and said movable contact in one direction with a snap action, uid pressure actuated means cooperable directly with the opposite face of said rigid plate to cause said flexible spring to displace said toggle and said movable contact in the opposite direction with a snap action, and means for varying the relative positions of said fixed and movable fulcmms to `alter the action of said toggle, said toggle spring being alternately directly engageable with said base and with said housing to posi tively limit the displacement of the toggle in opposite directions.

References Cited in the le of this patent UNITED STATES PATENTS 1,688,866 Hansen Oct. 23, 1928 1,858,005 Eggleston May 10, 1932 1,911,530 Raisch et al May 30, 1933 2,040,181 Mekelburg May 12, 1936 2,281,544 Beeman et al, May 5, 1942 2,413,130 Aitken Dec. 24, 1946 2,414,315 McCullough Jan. 14, 1947 2,444,529 Puster July 6, 1948 2,598,536 Hansen May 27, 1952 2,658,121 Gray et al. Nov, 3, 1953 2,738,397 Slonneger Mar. 13, 1956 FOREIGN PATENTS 79,494 Sweden Mar. 16, 1931 

